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How Low to Spin??
How Low to Spin??
I was proudly shown a IGC file this weekend. This file show the aero tow thru a thermal and a release into sink. Our proud pilot was unable to find the thermal and started a downwind leg for a landing. As he turned base leg, he flew into a 2-5 kt thermal. Instead of completing the pattern and landing, he turned and climbed in this thermal. The IGC file showed that his altitude at the time of encountering lift was 300 ft. I asked him 1 question as he displayed this flight on See You. How Low do you want to spin? His response scared me silly&&..My glider does not spin and there was no wind. He then continued to display the same flight where he bragged of spending a considerable amount of time in the mountains within 500 feet of the terrain. I am doubtful as to his ability to reach a landable area during this portion of the flight. This pilot is in his first year of private ownership, cross county soaring and may have almost 200 hours of total time. He has embraced soaring completely. I left the gliderport feeling that my suggestions as to his safety practices were just hollow words. I know that he reads RAS and would hope that the response to this post may give him some food for thought. |
#2
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He definitely sounds like an accident waiting to happen.
Not so much the fact that he did some questionable things, but the fact that he brags about them. Eventually he will hit some big sink while over the mountains, and realize he doesn't have an escape route. Hopefully the sink will let up before he crashes, and it will cause him to reevaluate his risk taking practices. Of course, it might just be occasion for him to brag again about what he got away with. |
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#4
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"Paul M. Cordell" wrote in message ... How Low to Spin?? I was proudly shown a IGC file this weekend. This file show the aero tow thru a thermal and a release into sink. Our proud pilot was unable to find the thermal and started a downwind leg for a landing. As he turned base leg, he flew into a 2-5 kt thermal. Instead of completing the pattern and landing, he turned and climbed in this thermal. The IGC file showed that his altitude at the time of encountering lift was 300 ft. I asked him 1 question as he displayed this flight on See You. How Low do you want to spin? His response scared me silly&&..My glider does not spin and there was no wind. He then continued to display the same flight where he bragged of spending a considerable amount of time in the mountains within 500 feet of the terrain. I am doubtful as to his ability to reach a landable area during this portion of the flight. This pilot is in his first year of private ownership, cross county soaring and may have almost 200 hours of total time. He has embraced soaring completely. I left the gliderport feeling that my suggestions as to his safety practices were just hollow words. I know that he reads RAS and would hope that the response to this post may give him some food for thought. I heard the following comment at an informal gathering of older pilots: "We old, cautious pilots were once young, bold pilots who scared ourselves badly enough to engender some wisdom before the youth and boldness killed us." And, "Good judgement is the distillation of bad experiences." Perhaps your pilot simply hasn't experienced the silent, deadly spin departure that can result from a turning stall in turbulent air. Maybe we just have to hope that he scares himself into wisdom. Maybe he needs a flight with a good instructor in an easily spinable trainer like a Blanik L-23 or most any eastern European two-seater. Practicing cross-controlled stalls in rough, mid-afternoon thermals will usually do the trick. By way of setting some perspective, I won't universally condemn low altitude saves. Sometimes thermalling away is the best option available. However, they are almost always the result of earlier bad decisions that placed the pilot in that situation. Getting low is the most common way of losing a contest day. Still, there are many pilots with whom I would feel comfortable as a passenger riding in the back seat as they thermalled up from 300 feet. They are good enough at sensing the early symptoms of a stall/spin that they would relax the backpressure for a moment and then continue the thermal turn without anyone but the most perceptive noticing what had happened. Usually, these are not pilots trained in 2-33's. Bill Daniels |
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Well 300'agl sounds about right for a proper base leg,
and if he had landable fields in all directions....so that if he circled in sink on the outside of the thermal...then in theory he might have been able to land even if he had not centered it and could not make the runway. I have experimented thermalling low right next to a runway when conditions and traffic permit...and u can burn 300' in one orbit. IMHO 600'-800'agl gives you more leeway, take another tow if u get below that...it is cheaper then funeral expenses. And never thermal in the pattern without thorough knowledge of the field and traffic procedures, and with a working radio I would think |
#6
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Part 2 of response-
Pushing limits safely is one of the appealing aspects of our sport...once one can actually stay up, this progression seems to be... 1.) How long(duration) 2.) How high 3.) How far 4.) How fast (How low) seems to fit in there somewhere...but it can bite harder then the others. One drill I was taught..figure out what the sink rate might be for a particular day if you hit the wrong part of a thermal...at a safe altitude pop your spoilers to that sink rate...then start circling to learn how much altitude you loose. As with many learning guidelines...the best instructors/mentors can relay this sort of information in a non-confrontional tone...which may aid learning. Sometimes RAS is lacking in this area |
#7
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In article ,
Stewart Kissel wrote: Part 2 of response- Pushing limits safely is one of the appealing aspects of our sport...once one can actually stay up, this progression seems to be... 1.) How long(duration) 2.) How high 3.) How far 4.) How fast An excellent list...how true... (How low) seems to fit in there somewhere...but it can bite harder then the others. I saw an accident report that noted the cause: "Pilot's inability to maintain terrain clearance." Boy, that is SOME lazy investigator...I laughed a tiny bit, and then was embarrassed at myself because it was a fatality... I read a lot of reports about accidents caused not by lack of lift, but presence of sink. In my close calls, I was always glide ratio or better to an airport, but this meant absolutely nothing. Sink is the killer. -- ------------+ Mark Boyd Avenal, California, USA |
#8
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Paul M. Cordell wrote:
How Low to Spin?? I was proudly shown a IGC file this weekend. This file show the aero tow thru a thermal and a release into sink. Our proud pilot was unable to find the thermal and started a downwind leg for a landing. As he turned base leg, he flew into a 2-5 kt thermal. Instead of completing the pattern and landing, he turned and climbed in this thermal. The IGC file showed that his altitude at the time of encountering lift was 300 ft. I asked him 1 question as he displayed this flight on See You. How Low do you want to spin? His response scared me silly&&..My glider does not spin and there was no wind. He then continued to display the same flight where he bragged of spending a considerable amount of time in the mountains within 500 feet of the terrain. I am doubtful as to his ability to reach a landable area during this portion of the flight. This pilot is in his first year of private ownership, cross county soaring and may have almost 200 hours of total time. He has embraced soaring completely. I left the gliderport feeling that my suggestions as to his safety practices were just hollow words. I know that he reads RAS and would hope that the response to this post may give him some food for thought. While getting shot down west of Boulder the other day, I was contemplating the "How low to circle?" equation. While always within EASY glide of the airport, I was low over the foothills. It wasn't a particularly "sinky" day, but down low the thermals were really just narrow threads of lift coming off the rocks. I realized that I'd need 500' or so to recover from a spin in a panic situation, and still need glide to the airport once I recovered my composure. If I got into a spin I'd also better have room to maneuver on the heading I recovered with. How many of us practice spin recovery to a heading, low, over rocks? =0 Circling down low whether over hills or flat ground presents complications in visual perspective that have been thoroughly addressed here in the past (Google some or Eric June's posts about his crash for a start) As Stu said, 600-800 feet of air underneath is a pretty good recommendation to *live* by. Interesting thing about the flight; By following the ridge lines keeping wind and sun in mind, I was able to run out of the hills at 300-400 feet over the ridges, maintaining my altitude until I had enough altitude to circle comfortably (which, remember includes the thermals spreading out enough to be useful). Just for good measure, later in the flight I did some practice turning stalls, to make sure my stall warning calibration was reasonable. YMMV, but for recreational pilots like me, these are good guidelines. Shawn |
#9
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In article ,
scurry wrote: Paul M. Cordell wrote: How Low to Spin?? When I flew my minature CA state record, at one point I had picked a field and was on downwind for landing. The stupid road on the field was 2000 ft long, but there were trees 50-100ft+ on both ends, and a tree right in the middle of the packed dirt road. I remember grumbling to myself that this could very possibly suck. I caught some lift on the downwind at about 500 ft AGL, right over the field. I circled fast and with shallow bank right over the field, in a wide arc. At every moment, I said I wouldn't get slow and tight close to the ground, and if I wasn't going up, I would go back to the downwind. 1 knot became 2, and soon I was at 1500AGL. I looked around a bit more, and found that I had set up for a tailwind landing (about 5 knots). I hadn't seen any flags or such on the way in, and the wind was 120 deg from what I expected. I tightened up and took a breath, and eventually held the same thermal up 10,000 ft, 4-6 knots. So mediocre landing field vs. 500ft shallow circle at higher speed? I'm gonna say that if I'm always in a position to make a safe landing, I'm ok. The real question is if someone flys slow and steep close to the ground. I do it high all the time, but never below 1000 feet AGL... -- ------------+ Mark Boyd Avenal, California, USA |
#10
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scurry wrote:
Interesting thing about the flight; By following the ridge lines keeping wind and sun in mind, I was able to run out of the hills at 300-400 feet over the ridges, maintaining my altitude until I had enough altitude to circle comfortably (which, remember includes the thermals spreading out enough to be useful). Ridge flying is practised currently *much* closer to the ridge than that, in fact so close than not touching some tree is the real problem. -- Michel Talon |
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